Hindu Undivided Family now needs to get separated

Sir, This is Akash garg from West-Bengal. I need an advice with the following points. We have an Hindu undivided Family and all business are Managed in joint My Father are two brothers at present working in the same business. two other brothers were separated long time back with relevant cash at that period. Now my Father and his elder brother are the two managing persons. Father elder brother has 4 sons and even they are now managing the business and have legally named all property on their name. We have 4 assets out of which one is very old and all seems to be in their name i.e my father elder brother sons. Now we want to get separated from this joint venture. Need to know what legal actions can be taken against them if they try to cheat my father as they have always been doing the same. We peacefully want our share and nothing else , but if cheated need to take legal actions against them. Please let me know what measures can be taken in father favor so that he get his share in the property.